The legislation goes to the state Senate, where a similar version was approved in 2009. Senate President John Cullerton’s spokeswoman said this week he supports the legislation.

The measure gives a framework for a four-year pilot program that includes requiring patients and caregivers to undergo background checks. The legislation sets a 2.5 ounce limit per patient per purchase.

Supporters say marijuana can relieve continual pain without triggering the harmful effects of other prescription drugs. Opponents say the program would encourage the use of marijuana for recreational purposes.